Agricultural Benefits

Biosolids improve soil. Biosolids provide much needed organic matter and essential plant nutrients. This organic matter improves soil structure and acts like a sponge to help retain moisture and holds nutrients for future use by plants and microorganisms. The nutrients in biosolids are slowly released as plants need them. Biosolids contain many essential plant nutrients, including the primary macronutrients nitrogen, phosphorus, and, to a lesser extent, potassium; they also contain secondary macronutrients magnesium, calcium and sulfur; and micronutrients such as copper, zinc, iron, manganese, molybdenum and boron.

Chemically, biosolids increase the soil’s “cation exchange capacity” (CEC), which is a measure of how well soil retains certain plant nutrients. The organic matter in biosolids acts like a magnet that holds and attracts plant nutrients keeping them in the root zone and preventing them from migrating or running off.

The agricultural benefits of biosolids have been documented for many decades by numerous scientific studies and through the practical experience of thousands of farmers. In Virginia, farmers report that the application of biosolids to land can, in some cases, more than double crop productivity. And since biosolids are used to replace chemical fertilizer applications, farmers not only prevent nutrient runoff but can save $350 an acre or more when biosolids are applied, compared to the cost of commercial fertilizer.